A spending watchdog has accused the Government of trying to conceal details of a troubled flagship benefit project.

The Commons Public Accounts Committee raised concerns that the decision to award the Universal Credit scheme a "reset" rating was "an attempt to keep information secret and prevent scrutiny".

The move meant the project was not ranked by the Major Projects Authority (MPA), on a five-tier traffic light system running from green to red, in this year's annual report.

The MPA confirmed the decision to give it a reset rating had been taken by ministers in the Department for Work and Pensions.

The "reset" category was introduced for the 2013-14 report and was only applied to this single project.

In their report, the MPs said: "We are particularly concerned that the decision to award a 'reset' rating to the Universal Credit project was an attempt to keep information secret and prevent scrutiny."

But ministers have insisted the scheme is on track and would realise its aim to get people into work and simplify the benefits system.

The committee also highlighted "serious weaknesses" in the Government's ability to deliver major projects, ranging from building ships and motorways, through to overhauling Government departments.

The report said: "These projects represent a considerable and rising cost to the taxpayer: the MPA reported in May 2014 that the whole life cost of these projects was £488bn, an increase of some £134bn on the previous year."

The MPs called for the MPA, which was set up to improve project delivery by Whitehall departments, to be given beefed up powers and to focus on departments such as health and defence, where there were a number of risky projects.

The committee also said said the Treasury should be given overall responsibility for overseeing the portfolio of major projects, rather than treating them as individual schemes.